Preparation method of deformed Ti2AlNb alloy and prepared deformed Ti2AlNb alloy

Abstract

The invention relates to the technical field of Ti2AlNb-based alloys, in particular to a preparation method of a deformed Ti2AlNb alloy and the deformed Ti2AlNb alloy prepared through the preparation method. The preparation method comprises the following steps: (a) carrying out cogging forging on a Ti2AlNb alloy ingot in T1, and then carrying out step-by-step cooling forging in a range of 940-1100 DEG C to obtain an intermediate billet; (b) processing the intermediate blank in T2, and then carrying out heat treatment; in the machining process, the deformation of a single heating number is 20%-85%; t1 is 1100 DEG C to 1200 DEG C, and T2 is 960 DEG C to 1060 DEG C; and in the step-by-step cooling forging, the final forging temperature is 940-1040 DEG C, and T2 is 20-120 DEG C higher than the final forging temperature. According to the method, the original structure of the Ti2AlNb alloy cast ingot can be refined, the structure uniformity is improved, and meanwhile the mechanical property and the yield of the alloy can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of Ti2AlNb-based alloys, and in particular to a preparation method of a deformed Ti2AlNb alloy and the prepared deformed Ti2AlNb alloy. Background Art

[0002] Ti2AlNb alloy is a lightweight high-temperature structural material that can be used for a long time at 600-750℃ or for a short time at a higher temperature. Ti2AlNb alloy is an intermetallic compound alloy. Due to its long-range order in crystal structure and strong bonding force between metal atoms, it has the advantages of excellent high-temperature specific strength and specific modulus, and good creep resistance. The above excellent properties make it show great application potential in aerospace structural materials, which is of great significance for improving the thrust-to-weight ratio of aircraft, improving fuel efficiency and high-temperature service performance.

[0003] In terms of engineering applications of Ti2AlNb alloys, deformed Ti2AlNb alloys have the highest maturity and the widest application. However, deformed Ti2AlNb alloys currently have common problems such as coarse grains, uneven structure, and large performance fluctuations, which seriously restrict their engineering applications in aerospace structural parts.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] An object of the present invention is to provide a method for preparing a deformed Ti2AlNb alloy, which can refine the original structure of the Ti2AlNb alloy and improve the uniformity of the structure.

[0006] Another object of the present invention is to provide a deformed Ti2AlNb alloy prepared by the above preparation method.

[0007] In order to achieve the above-mentioned object of the present invention, the present invention provides a method for preparing a deformed Ti2AlNb alloy, comprising the following steps:

[0008] (a) The Ti2AlNb alloy ingot is forged at T1, and then forged step by step at a temperature range of 940-1100°C to obtain an intermediate billet;

[0009] (b) processing the intermediate blank at T2 and then performing heat treatment;

[0010] In step (b), during the processing, the deformation amount of a single firing is 20% to 85%;

[0011] The T1 and T2 are 1100-1200° C. and 960-1060° C. respectively; in the step-by-step temperature-dropping forging, the final forging temperature is 940-1040° C., and the T2 is 20-120° C. higher than the final forging temperature.

[0012] In a specific embodiment of the present invention, the step-by-step temperature reduction forging includes at least two forging stages.

[0013] In a specific embodiment of the present invention, the step-by-step cooling forging includes a first forging stage and a second forging stage. The temperature of the first forging stage is 1050-1100°C, and the temperature of the second forging stage is 940-1000°C.

[0014] In another specific embodiment of the present invention, the step-by-step cooling forging includes a first forging stage, a second forging stage and a third forging stage, the temperature of the first forging stage is 1050-1100°C, the temperature of the second forging stage is 1000-1050°C, and the temperature of the third forging stage is 940-1000°C.

[0015] In a specific embodiment of the present invention, during the blank forging, the Ti2AlNb alloy ingot is repeatedly upset and drawn.

[0016] In a specific embodiment of the present invention, in the blank forging, the deformation amounts of upsetting and drawing in each fire are 20% to 50% respectively.

[0017] In a specific embodiment of the present invention, in the step-by-step cooling forging, the deformation amount of upsetting and / or drawing in each forging stage is 20% to 50% in each fire.

[0018] In a specific embodiment of the present invention, in step (b), the processing includes rolling or forging. Further, the processing includes at least one round of rolling or forging.

[0019] In a specific embodiment of the present invention, in step (b), during the rolling, the total deformation is 30% to 90%.

[0020] In a specific embodiment of the present invention, the heat treatment includes solution treatment and aging treatment. Further, the solution treatment includes: keeping at 940-1000°C for 2-8 hours, and cooling to room temperature in a water-soluble quenching medium or mineral oil. The aging treatment includes: keeping at 760-900°C for 4-60 hours, and air cooling to room temperature.

[0021] Another aspect of the present invention provides a deformed Ti2AlNb alloy prepared by any one of the above-mentioned methods for preparing the deformed Ti2AlNb alloy.

[0022] In a specific embodiment of the present invention, the deformed Ti2AlNb alloy has a dual-size lath structure. Further, the dual-size lath structure includes O-phase coarse laths and O-phase fine laths; the O-phase coarse laths satisfy: a length of 1 to 10 μm, a width of 0.5 to 2 μm, and a volume fraction of 10% to 60%, and the O-phase fine laths satisfy: a length of ≤3 μm, a width of ≤0.5 μm, and a volume fraction of 40% to 90%.

[0023] In a specific embodiment of the present invention, in the deformed Ti2AlNb alloy, the average grain size of B2 is less than 300 μm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention adopts a method of successive temperature reduction forging to refine the original structure of the Ti2AlNb alloy ingot and improve the uniformity of the structure, and then performs a large deformation near the B2 / β transformation point, and then cooperates with heat treatment to obtain a deformed Ti2AlNb alloy with uniform structure, stable performance and good comprehensive performance;

[0026] (2) The deformed Ti2AlNb alloy prepared by the method of the present invention has a dual-size lath structure, so that the deformed Ti2AlNb alloy has good matching of strength and plasticity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A schematic diagram of a process route for deforming Ti2AlNb alloy provided in an embodiment of the present invention;

[0029] Figure 2 The microstructure diagram of the Ti2AlNb alloy ingot after low temperature forging provided in Example 1 of the present invention;

[0030] Figure 3 The microstructure diagram of the Ti2AlNb alloy obtained in step (4) of Example 1 of the present invention;

[0031] Figure 4 This is a microstructure diagram of the Ti2AlNb alloy after solid solution and aging treatment provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0033] Based on the problems of coarse grains, uneven structure, low hot working plasticity and easy cracking in existing Ti2AlNb alloys, the present invention provides a method for preparing a deformed Ti2AlNb alloy, comprising the following steps:

[0034] (a) The Ti2AlNb alloy ingot is forged at T1, and then forged step by step at a temperature range of 940-1100°C to obtain an intermediate billet;

[0035] (b) processing the intermediate billet at T2 and then performing heat treatment;

[0036] In step (b), during processing, the deformation amount of a single fire is 20% to 85%;

[0037] T1 and T2 are 1100-1200°C and 960-1060°C respectively; in the step-by-step cooling forging, the final forging temperature is 940-1040°C, and T2 is 20-120°C higher than the final forging temperature.

[0038] In the preparation of the deformed Ti2AlNb alloy of the present invention, the Ti2AlNb alloy ingot is firstly forged at a relatively high temperature above the B2 phase transformation point. On the one hand, the plasticity is good and not easy to crack during high temperature forging, and the hot working plasticity of the ingot is improved by high temperature forging, providing a good hot working plasticity foundation for subsequent processing; then the temperature is gradually reduced forging, the original structure of the ingot is broken by deformation and recrystallization, and the B2 grain size is refined, the hot working plasticity of the alloy is gradually improved, and the cracking tendency of the Ti2AlNb alloy during low temperature deformation is weakened, and the final forging temperature is controlled at or below the α2+B2 two-phase region, and sufficient distortion energy is accumulated in the Ti2AlNb alloy through low temperature deformation, and α2 / O phase particles are precipitated at the same time. Then, a formed blank is obtained by a high temperature large deformation method, and the α2 / O phase particles formed in the low temperature deformation structure are used to prevent the growth of the B2 / β grain size during high temperature T2 treatment, and the grain boundary is broken by large deformation to further refine the structure. In addition, the present invention obtains the formed blank by a large deformation method, which not only reduces the number of deformation and firing, but also improves the mechanical properties of the alloy.

[0039] The final forging temperature is within the above range, between the α2+O+B2 three-phase region and the α2+B2 two-phase region. On the one hand, it avoids excessive deformation resistance due to low temperature, which makes it difficult for ordinary tonnage forging machines to forge, and avoids poor plasticity due to low temperature, which causes cracking during deformation and reduces material utilization. On the other hand, it avoids grain coarsening due to high temperature.

[0040] For example, in different embodiments, T1 may be 1100°C, 1120°C, 1150°C, 1180°C, 1200°C or a range consisting of any two thereof, and T2 may be 940°C, 950°C, 960°C, 970°C, 980°C, 990°C, 1000°C, 1010°C, 1020°C, 1030°C, 1040°C, 1050°C, 1060°C or a range consisting of any two thereof. In the step-by-step cooling forging, the forging temperature can be 940°C, 980°C, 1000°C, 1020°C, 1050°C, 1080°C, 1100°C or a range consisting of any two thereof, and the temperature of the last stage forging is controlled between 940 and 1040°C, such as 940°C, 960°C, 980°C, 1000°C, 1020°C, 1040°C or a range consisting of any two thereof, and the final forging temperature and T2 satisfy: T2 is 20 to 120°C higher than the final forging temperature, such as T2 can be 20°C, 40°C, 50°C, 60°C, 80°C, 100°C, 120°C or a range consisting of any two thereof higher than the final forging temperature.

[0041] It should be noted that the deformation of the present invention is the deformation in the thickness direction, and the specific calculation method is: assuming that the initial thickness of the blank is H0, and the thickness of the blank after deformation is H1, the corresponding deformation = (H0-H1) ÷ H0. For example, in different embodiments, in step (b), during processing, the deformation of a single fire can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or a range composed of any two of them. The deformation within the above deformation range is carried out at T2, taking into account the guarantee of the crushing of equiaxed crystals to achieve grain refinement and avoid the performance differences in different directions of the alloy caused by the generation of texture. If the deformation is too low, the equiaxed crystals formed during the insulation process will be incompletely crushed, resulting in a decrease in the plasticity of the alloy; if the deformation is too large, texture is easily generated, increasing the performance differences of the alloy in different directions.

[0042] The heat preservation time within each temperature range can be adjusted and selected according to the conventional heat treatment heat preservation time in the art.

[0043] In a specific embodiment of the present invention, the step-by-step temperature reduction forging includes at least two forging stages.

[0044] In a specific embodiment of the present invention, the step-by-step cooling forging includes a first forging stage and a second forging stage. The temperature of the first forging stage is 1050-1100°C, and the temperature of the second forging stage is 940-1000°C.

[0045] For example, in different embodiments, the temperature of the first forging stage can be 1050°C, 1060°C, 1070°C, 1080°C, 1090°C, 1100°C or a range consisting of any two thereof, and the temperature of the second forging stage can be 940°C, 950°C, 960°C, 970°C, 980°C, 990°C, 1000°C or a range consisting of any two thereof.

[0046] The schematic diagram of the process route for deforming Ti2AlNb alloy provided in this embodiment is shown in FIG. Figure 1 Since the initial grain size of the ingot is coarse, the deformation temperature used in the blank forging is relatively high. The blank forging refines the grains and improves the hot working plasticity. By setting the temperature of the first forging stage to still be above the B2 phase transformation point, the grains are further refined to avoid the grains being too coarse during the next deformation, which will cause the alloy to crack during the deformation process.

[0047] In another specific embodiment of the present invention, the step-by-step cooling forging includes a first forging stage, a second forging stage and a third forging stage. The temperature of the first forging stage is 1050-1100°C, the temperature of the second forging stage is 1000-1050°C, and the temperature of the third forging stage is 940-1000°C.

[0048] In a specific embodiment of the present invention, during the blank forging, the Ti2AlNb alloy ingot is repeatedly upset and drawn. Further, the number of upsetting and drawing is ≥ 2 times, such as 2 to 4 times.

[0049] In actual operation, during the process of forging, when the temperature drops, the hot material can be returned to the furnace.

[0050] In a specific embodiment of the present invention, in the blank forging, the deformation amounts of upsetting and drawing in each fire are 20% to 50% respectively.

[0051] For example, in different embodiments, in the open forging, the deformation amount of upsetting and drawing in each fire can be 20%, 25%, 30%, 35%, 40%, 45%, 50% or a range composed of any two of them. The deformation amount of upsetting and drawing is regulated within the above range to ensure hot working plasticity while refining the grains.

[0052] In a specific embodiment of the present invention, in the step-by-step cooling forging, the deformation amount of upsetting and / or drawing in each forging stage is 20% to 50% in each fire.

[0053] In actual operation, the preparation method of the present invention can be used to prepare bars, rings, plates, etc., and the specific processing methods of each stage can be regulated and selected according to the size specifications of the target structure. In actual operation, in each forging stage of the step-by-step cooling forging, repeated upsetting operations can be performed, and the specific number of upsetting operations can be ≥6 times, such as 6 to 10 times, but is not limited thereto.

[0054] For example, when alloy ingots are used to prepare plates, in the last forging stage of step-by-step cooling forging, the forging method can be as follows, but not limited to: the blank is first upset along the thickness direction, then first drawn along the width direction, and then second drawn along the thickness direction to obtain an intermediate blank.

[0055] In actual operation, during the step-by-step cooling forging process, when the temperature drops, the hot material can be returned to the furnace.

[0056] In a specific embodiment of the present invention, in step (b), the processing includes rolling or forging. Further, the processing includes at least one round of rolling or forging.

[0057] The processing method may include rolling or forging, which can be adjusted according to the actual product specifications. In actual operation, rolling can be carried out on a rolling mill, and rolling can be carried out once, and then the hot material is returned to the furnace and then rolled again to ensure that the total deformation is within the above range.

[0058] In a specific embodiment of the present invention, in step (b), during rolling, the total deformation is 30% to 90%.

[0059] For example, in different embodiments, in step (c), during rolling, the total deformation can be 30%, 40%, 50%, 60%, 65%, 70%, 75%, 80%, 90% or a range consisting of any two thereof.

[0060] In a specific embodiment of the present invention, the heat treatment includes solution treatment and aging treatment. Further, the solution treatment includes: keeping at 940-1000°C for 2-8 hours, cooling to room temperature in a water-soluble quenching medium or mineral oil. The aging treatment includes: keeping at 760-900°C for 4-60 hours, and air cooling to room temperature.

[0061] Among them, the holding temperature of the solution treatment can be 940℃, 950℃, 955℃, 960℃, 965℃, 970℃, 980℃, 990℃, 1000℃ or a range composed of any two of them, and the holding time can be 2h, 3h, 4h, 6h, 8h, etc.; the holding temperature of the aging treatment can be 760℃, 770℃, 775℃, 780℃, 785℃, 790℃, 800℃, 820℃, 850℃, 880℃, 900℃ or a range composed of any two of them, and the holding time can be 4h, 8h, 12h, 16h, 20h, 24h, 28h, 32h, 40h, 48h, 60h, etc.

[0062] The water-soluble quenching medium includes PAG quenching liquid, wherein the mass fraction of the polyalkylene glycol aqueous solution in the PAG quenching liquid is 5% to 20%.

[0063] Another aspect of the present invention provides a deformed Ti2AlNb alloy prepared by any one of the above-mentioned methods for preparing the deformed Ti2AlNb alloy.

[0064] In a specific embodiment of the present invention, the deformed Ti2AlNb alloy has a dual-size lath structure. Further, the dual-size lath structure includes O-phase coarse laths and O-phase fine laths; the O-phase coarse laths satisfy: a length of 1 to 10 μm, a width of 0.5 to 2 μm, and a volume fraction of 10% to 60%; the O-phase fine laths satisfy: a length of ≤3 μm, a width of ≤0.5 μm, and a volume fraction of 40% to 90%.

[0065] In a specific embodiment of the present invention, in the deformed Ti2AlNb alloy, the average B2 grain size is less than 300 μm.

[0066] The nominal composition of the Ti2AlNb alloy of the present invention is Ti-22Al-25Nb (at.%, atomic percentage), but is not limited thereto, and any other Ti2AlNb-based alloy may be used.

[0067] Example 1

[0068] This embodiment provides a method for preparing a deformed Ti2AlNb alloy, comprising the following steps:

[0069] (1) Select the size The Ti2AlNb alloy ingot was forged after being kept at 1170℃ for 5h. The first fire was upsetting to Then it is drawn to a square billet with a size of X×Y×Z=450mm×450mm×920mm (the dimensions in the X and Y directions are the radial dimensions of the original ingot, and the dimension in the Z direction is the axial dimension of the original ingot); then the hot material is returned to the furnace for a heat preservation treatment at 1170°C for 3h, and the second fire forging is carried out, firstly upsetting to obtain a square billet with a size of X×Y×Z=585mm×585mm×550mm, and then drawn to obtain a square billet with a size of X×Y×Z=450mm×450mm×920mm; the hot material returning to the furnace and forging process of the second fire are repeated, and after the third fire forging is completed, comprehensive grinding is carried out to remove oxide scale and cracks on the surface of the alloy.

[0070] (2) The square billet after grinding in step (1) is charged into a furnace and kept at 1080° C. for 5 h. After the heat preservation is completed, the fourth forging is performed, and the square billet with a size of X×Y×Z=450 mm×450 mm×920 mm is upset to a square billet with a size of X×Y×Z=585 mm×585 mm×550 mm, and then stretched to a square billet with a size of X×Y×Z=450 mm×450 mm×920 mm; then the hot material is returned to the furnace for heat preservation treatment at 1080° C. for 3 h. After the heat preservation treatment is completed, the fifth forging is performed (the fifth forging repeats the forging process of the fourth forging); then the sixth forging is performed, and the sixth forging repeats the hot material returning and forging process of the fifth forging; after the sixth forging is completed, comprehensive grinding is performed to remove oxide scale and cracks on the surface of the alloy. The polished billet is forged in the seventh, eighth and ninth fires. The hot material return and forging process of each fire are the same as those of the fourth, fifth and sixth fires respectively. After the ninth fire forging is completed, it is fully polished to remove the oxide scale and cracks on the alloy surface.

[0071] (3) The square billet after grinding in step (2) is charged into a furnace and kept at 980° C. for 5 h. After the end of the heat preservation, the tenth fire forging is performed. The square billet is first upset to obtain a square billet with a size of X×Y×Z=580 mm×580 mm×540 mm, and then stretched to obtain a billet with a size of X×Y×Z=540 mm×780 mm×430 mm. The hot material is then returned to the furnace for a heat preservation treatment at 980° C. for 3 h. After the end of the heat preservation, the eleventh fire forging is performed to obtain a billet with a size of X×Y×Z=5 The billet is 90mm×900mm×340mm, and then the hot material is returned to the furnace for a heat preservation treatment at 980℃ for 2.5h. After the heat preservation, the twelfth fire forging is performed, and the billet with a size of X×Y×Z=740mm×900mm×270mm is drawn. Then the hot material is returned to the furnace for a heat preservation treatment at 980℃ for 2h. After the heat preservation, the thirteenth fire forging is performed, and the billet with a size of X×Y×Z=900mm×900mm×220mm is drawn. Then it is fully polished to remove the oxide scale and cracks on the surface of the alloy. After polishing, machining is performed to improve the surface quality and flatness of the slab. The size after machining is X×Y×Z=860mm×860mm×210mm.

[0072] (4) The billet obtained in step (3) is charged into a furnace and kept at 1060° C. for 2 h. After the end of the heat preservation, it is rolled to obtain a billet with a size of X×Y×Z=860 mm×1640 mm×110 mm; then the hot material is returned to the furnace for a heat preservation treatment at 1060° C. for 1 h. After the end of the heat preservation, it is reversed and rolled to obtain a slab with a size of X×Y×Z=1892 mm×1640 mm×50 mm.

[0073] (5) Cut a test piece with a size of X×Y×Z=150 mm×1640 mm×50 mm from the slab of step (4), and perform solution treatment and aging treatment to obtain a deformed Ti2AlNb alloy; wherein the solution treatment comprises: keeping at 960°C for 3 h and then cooling in a PAG extract; and the aging treatment comprises: keeping at 780°C for 24 h and then air cooling.

[0074] Example 2

[0075] This example is prepared by referring to the method of Example 1, with the only difference being that step (4) is different.

[0076] Step (4) of this embodiment comprises: charging the billet obtained in step (3) into a furnace and keeping it at 1060°C for 2 hours, and rolling it after the end of the insulation to obtain a billet with a size of X×Y×Z=860mm×1330mm×135mm; then returning the hot material to the furnace for a heat treatment at 1060°C for 1 hour, and performing reversing rolling after the end of the insulation to obtain a slab with a size of X×Y×Z=1365mm×1330mm×85mm; then returning the hot material to the furnace for a heat treatment at 1060°C for 1 hour, and performing reversing rolling after the end of the insulation to obtain a slab with a size of X×Y×Z=1365mm×2260mm×50mm.

[0077] Example 3

[0078] This example is prepared by referring to the method of Example 1, with the only difference being that step (4) is different.

[0079] Step (4) of this embodiment includes: charging the billet obtained in step (3) into a furnace and keeping it at 1060°C for 2 hours, and rolling it after the insulation is completed to obtain a billet with a size of X×Y×Z=860mm×2778mm×65mm; then returning the hot material to the furnace for insulation treatment at 1060°C for 1 hour, and reversing rolling after the insulation is completed to obtain a slab with a size of X×Y×Z=1397mm×2778mm×40mm.

[0080] Example 4

[0081] This example is prepared by referring to the method of Example 1, with the only difference being that step (4) is different.

[0082] Step (4) of this embodiment comprises: charging the billet obtained in step (3) into a furnace and keeping it at 1060° C. for 2 hours, rolling it after the end of the heat preservation, and rolling to obtain a billet with a size of X×Y×Z=860mm×1090mm×165mm; then returning the hot material to the furnace for heat preservation at 1060° C. for 1 hour, and reversing rolling after the end of the heat preservation, and rolling to obtain a slab with a size of X×Y×Z=1090mm×1090mm×130mm; then returning the hot material to the furnace for heat preservation at 1060° C. for 1 hour, and reversing rolling after the end of the heat preservation, and rolling to obtain a slab with a size of X×Y×Z=1090mm×1090mm×130mm; then returning the hot material to the furnace for heat preservation at 1060° C. for 1 hour, and Reversing rolling is carried out to obtain a slab with dimensions of X×Y×Z=1090mm×1417mm×100mm; then the hot material is returned to the furnace for insulation treatment at 1060℃ for 1h, and after the insulation is completed, reversing rolling is carried out to obtain a slab with dimensions of X×Y×Z=1362mm×1417mm×80mm; then the hot material is returned to the furnace for insulation treatment at 1060℃ for 1h, and after the insulation is completed, reversing rolling is carried out to obtain a slab with dimensions of X×Y×Z=1362mm×2267mm×55mm.

[0083] Example 5

[0084] This example is prepared by referring to the method of Example 1, with the only difference being that step (4) is different.

[0085] Step (4) of this embodiment includes: charging the billet obtained in step (3) into a furnace and keeping it at 1060°C for 2 hours, and rolling it after the end of the insulation to obtain a slab with a size of X×Y×Z=860mm×5160mm×35mm.

[0086] Example 6

[0087] This example is prepared by referring to the method of Example 1, with the only difference being that the insulation temperature in step (2) is different.

[0088] In step (2) of this embodiment, the insulation temperature is 1040°C.

[0089] Comparative Example 1

[0090] Comparative Example 1 refers to the preparation method of Example 1, except that the insulation temperature in step (3) is different.

[0091] The insulation temperature in step (3) of Comparative Example 1 is 930°C.

[0092] Comparative Example 2

[0093] Comparative Example 2 refers to the preparation method of Example 1, except that the insulation temperature in step (3) is different.

[0094] The insulation temperature in step (3) of Comparative Example 2 is 1050°C.

[0095] Comparative Example 3

[0096] Comparative Example 3 refers to the preparation method of Example 1, except that the insulation temperatures in step (1) and step (2) are different.

[0097] The insulation temperature in step (1) of comparative example 3 is 1080°C, and the insulation temperature in step (2) is 1040°C.

[0098] Comparative Example 4

[0099] Comparative Example 4 refers to the preparation method of Example 1, except that step (2) is not included.

[0100] Experimental example

[0101] Figure 2 The microstructure diagram of the Ti2AlNb alloy ingot provided in Example 1 of the present invention; Figure 3 The microstructure diagram of the Ti2AlNb alloy obtained in step (4) of Example 1 of the present invention; Figure 4The microstructure diagram of the Ti2AlNb alloy after solution and aging treatment provided in Example 1 of the present invention. As can be seen from the figure, the grain size of the Ti2AlNb alloy ingot is coarse, and after the treatment of steps (1) to (4) of the present invention, the structure can be refined, and after solution and aging treatment, a double lath structure is obtained.

[0102] The microstructures of different embodiments and comparative examples after solution treatment and aging treatment were further characterized and analyzed, and microstructure images were obtained using a scanning electron microscope. The volume fraction and size of the phases in the microstructure images were measured using Image-Pro Plus 6.0 software, and the results are shown in Table 1. The average size refers to the average size in the length direction.

[0103] Table 1 Microstructures after solution treatment and aging treatment in different embodiments and comparative examples

[0104]

[0105] The properties of the Ti2AlNb alloys obtained in different embodiments and comparative examples were tested. The room temperature tensile test standard was referred to GB / T 228.1, and the 650°C tensile test standard was referred to GB / T 228.2. The test results are shown in Table 2.

[0106] Table 2 Longitudinal mechanical properties of Ti2AlNb alloy plates after solution treatment and aging treatment in different embodiments and comparative examples

[0107]

[0108]

[0109] The yield rates of the preparation methods of different embodiments and comparative examples after deformation were further calculated, and the results are shown in Table 3.

[0110] Table 3 The yield rate of the methods of different embodiments and comparative examples

[0111]

[0112]

[0113] It can be seen from the above test results that the preparation method of the deformed Ti2AlNb alloy of the present invention can not only obtain the deformed Ti2AlNb alloy with uniform structure, but also improve the mechanical properties of the deformed Ti2AlNb alloy while ensuring a high yield rate.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a deformed Ti2AlNb alloy, characterized in that: The steps include: (a) The Ti2AlNb alloy ingot is forged at T1, and then forged step by step at a temperature range of 940 to 1100°C to obtain an intermediate billet; (b) processing the intermediate blank at T2 and then performing heat treatment; In step (b), during the processing, the deformation amount of a single firing is 20% to 85%; The T1 and T2 are 1100-1200° C. and 960-1060° C. respectively; in the step-by-step temperature-dropping forging, the final forging temperature is 940-1040° C., and the T2 is 20-120° C. higher than the final forging temperature.

2. The method for preparing a deformed Ti2AlNb alloy according to claim 1, characterized in that: The step-by-step cooling forging includes at least two forging stages; Preferably, the step-by-step cooling forging includes a first forging stage and a second forging stage, the temperature of the first forging stage is 1050-1100°C, and the temperature of the second forging stage is 940-1000°C.

3. The method for preparing a deformed Ti2AlNb alloy according to claim 1, characterized in that: The step-by-step cooling forging includes a first forging stage, a second forging stage and a third forging stage. The temperature of the first forging stage is 1050-1100°C, the temperature of the second forging stage is 1000-1050°C, and the temperature of the third forging stage is 940-1000°C.

4. The method for preparing a deformed Ti2AlNb alloy according to claim 1, characterized in that: During the blank forging, the Ti2AlNb alloy ingot is repeatedly upset and drawn; Preferably, in the blank forging, the deformation amounts of upsetting and drawing in each fire are 20% to 50% respectively.

5. The method for preparing a deformed Ti2AlNb alloy according to claim 1, characterized in that: In the step-by-step cooling forging, the deformation amount of upsetting and / or drawing in each forging stage and each firing is 20% to 50%.

6. The method for preparing a deformed Ti2AlNb alloy according to claim 1, characterized in that: In step (b), the processing includes rolling or forging; Preferably, the processing includes at least one rolling or forging; Preferably, during the rolling, the total deformation is 30% to 90%.

7. The method for preparing a deformed Ti2AlNb alloy according to claim 1, characterized in that: The heat treatment includes solution treatment and aging treatment; Preferably, the solution treatment comprises: keeping the temperature at 940-1000°C for 2-8 hours, and then cooling to room temperature in a water-soluble quenching medium or mineral oil; Preferably, the aging treatment comprises: keeping at 760-900° C. for 4-60 hours, and air cooling to room temperature.

8. Deformed Ti2AlNb alloy, characterized in that The deformed Ti2AlNb alloy is prepared by the preparation method of any one of claims 1 to 7.

9. The deformed Ti2AlNb alloy according to claim 8, characterized in that: The deformed Ti2AlNb alloy has a dual-size lath structure.

10. The deformed Ti2AlNb alloy according to claim 8, characterized in that: In the deformed Ti2AlNb alloy, the average grain size of B2 is less than 300 μm.

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